Numerical Simulation of Wave Propagation in Crystallized Dusty Plasmas: One Dimensional Model

F. S. Kuo

《Chinese Journal of Physics》 38卷4期 (2000/08) Pp. 825-840

並列摘要

A numerical code has been developed to study the wave propagation in crystallized dusty plasmas. In the one-dimensional model, we model a very long system by a finite number of dusty particles with the periodic boundary condition. Each simulation is characterized by k, the ratio of the inter-particle separation at equilibrium over the Debye length, and Г, the ratio of the characteristic inter-particle Coulomb potential energy over the thermal energy of the particles. Viscosity, finite-size effect and the thermal motion are ignored. Some interesting results have emerge from the systematic simulations: 1. The phase velocity of the wave propagation is nearly independent of its wave number at large inter-particle separation, k ＞ 2.0. Thus the disturbance of the Gaussian shape propagates like a solitary wave. 2. The propagation speed v of a Gaussian disturbance is strictly proportional to the square root of Г. 3. When k ≤ 2.0, the propagation speed v (expressed in terms of the thermal speed) of disturbance is very well fitted byv = √Г/196(-17.4 +41.6/√k)We further observe that solitary-wave-like propagation will appear when only the nearest neighbor force is effective. As the inter-particle separation becomes smaller, more interparticle forces other than the nearest neighbor force become effective, resulting in the widening of the difference between the phase velocities of low and high frequency waves. Therefore, this solitary-wave-like behavior does not appear in the wave propagation for small particle separation. We apply the result of our simulations to examine the polar mesosphere summer echo (PSME) event reported by Ref 1 [Alcala et al., Radio Science, 30, 1205 (1995)].